Certainly! Let's break down each part of the question related to different aspects of music:
The absence of a tonal center in music: This is referred to as 'Atonality'. Atonal music does not have a key center or tonal center, which means it doesn't rely on a specific scale or a tonic note like traditional tonal music does.
This style expresses intense emotions and inner conflicts: This style is known as 'Expressionism' in music. It emerged in the early 20th century and focuses on expressing deep, often unsettling emotions and psychological states.
La Mer and Prélude to the Afternoon of a Faun are examples of this style: Both of these pieces are examples of 'Impressionism' in music. This style is characterized by an emphasis on atmosphere and mood, rather than a strong sense of narrative or structure. Claude Debussy, the composer of both pieces, is a key figure in this style.
This technique uses actual recorded sounds edited into a collage: Known as 'Musique Concrète', this technique involves taking recorded natural sounds and manipulating them into a musical piece. It's a form of experimental music composition that originated in the 20th century.
Name of the piece where the performer sits silently for 4 minutes and 33 seconds: The piece is called "4'33" composed by John Cage. It's a unique work where musicians sit in silence for the duration of the piece, allowing the ambient sounds in the environment to become the music.
A musical era marked by experimentation, innovation, and rejection of traditional rules: This is known as the '20th Century Music' era. It was a time when composers broke away from traditional forms and experimented with new techniques and forms, resulting in a wide variety of styles like impressionism, expressionism, atonality, and more.
I hope this helps explain the various music concepts mentioned in your question!